Applicants"" invention relates to a method for making road base using primarily waste material from oil and gas waste solids and non-hazardous industrial waste or natural occurring porous or semi-porous material to create a asphalt stabilized road base that is environmentally safe and meets industry standards for quality materials. More particularly, it relates to combining, in a cold batch mixing process, treated oil and gas waste material with aggregate to provide the major components for the roadbed base material.
Because of their importance in all aspects of both business and private life, the construction of roads has historically been of prime importance to a society. That importance remains today. However, it has also become more apparent in recent years that most resources are not infinite but rather, are depletable. Additionally, disposing of waste materials is becoming harder and harder due both to space limitations and liability resulting from waste materials entering the environment.
Thus, there is a need for developing methods to recycle waste products into new, usable products. If the components of roadbeds can be obtained from the waste products of other products and processes, then both waste product production is decreased and new product consumption is decreased. Further, it is advantageous to recycle waste products due to the economic advantage of using recycling materials and thus compounding return on the original costs of the products.
The primary focus of the invention is the treatment of oil and gas waste for use with other materials to make a suitable road base material. Treatment of oil and gas waste is done to remove at least a portion of a liquid component, typically primarily oil and water to yield a treated oil and gas waste portion which is then combined with an aggregate and a binder and stabilizer to produce a suitable road base material. The treatment of the oil and gas waste, while yielding a liquid portion may also yield other recyclable or useable products such as clean mud. Clean mud is a product often desired by oil and gas well drillers. Thus, it is the desired result of the present invention of using oil and gas waste material treated such that it is converted into a material that is useable and, excepting perhaps xe2x80x9cwaste waterxe2x80x9d which may be reinjected, yields environmentally friendly, economically valuable components.
Turning to the separation of the liquid component from the oil and gas waste material it is anticipated by the present invention that there are a number of methods of liquid portion removal. One such method is a novel means of stacking of oil and gas waste, to yield gravity induced separation of some of the liquid portion from the solid portion. Another method is mechanical separation, such as by a centrifuge. A third method is mixing with a dry material, such, for example, as soil, overburden, or caliche limestone.
The present invention provides a novel method to produce road base material using waste products from one or both of two industries: oil and gas well drilling and from construction and/or demolition and manufacturing projects. The present invention also provides for a novel road base composition. The oilfield waste is typically comprised of hazardous and/or non-hazardous oilfield solid or liquid waste such as water based drilling fluid, drill cuttings, and waste material from produced water collecting pits, produced formation sand, oil based drilling mud and associated drill cuttings, soil impacted by crude oil, dehydrated drilling mud, waste oil, spill sites and other like waste materials tank bottoms, pipeline sediment and spillsite waste. Oilfield waste may include waste or recycled motor oil, petroleum based hazardous or non-hazardous materials, such oilfield waste materials are collectively referred to as xe2x80x9coil and gas waste material.xe2x80x9d They typically have a solid component and a liquid component, the liquid component including quantities of oil and water. The solid components may be, in part, particulate.
An aggregate component of the road based material may include a non-hazardous industrial waste as defined in more detail below or any natural occurring stone aggregate such as limestone, rip rap, caliche, sand, overburden, or any other naturally occurring porous material. There may or may not be preparation of the aggregate material prior to combining with the treated oil and gas material to form the primary component of the road based material of Applicant""s present invention.
The construction and/or demolition or manufacturing waste component of the aggregate material is typically comprised of non-hazardous industrial waste such as waste concrete, waste cement, waste brick material, gravel, sand, and other like materials obtained as waste from industrial construction, demolition sites, and/or manufacturing sites. Such materials are collectively referred to as xe2x80x9cnon-hazardous industrial waste.xe2x80x9d
One application of the method of the present invention provides for recycling the oil and gas waste material and the non-hazardous industrial waste to combine to produce road base. Another application of the present invention provides for recycling the oil and gas waste material and an aggregate including limestone, rip rap, caliche, or any naturally occurring porous or semi-porous material to combine to produce road base. Hydration and mixing of the treated oil and gas waste material and aggregate along with a binder such as cement, fly ash, lime, kiln dust or the like, will achieve an irreversible pozzolanic chemical reaction necessary for a road base. An asphalt emulsifier may be included in the binder to manufacture asphalt stabilized road base. The ingredients are typically mixed in a cold batch process.
Solid waste from the oil and gas waste material typically contains naturally occurring aluminas and silicas found in soils and clays. The added pozzolan will typically contain either silica or calcium ions necessary to create calcium-silica-hydrates and calcium-aluminate-hydrates. A pozzolan is defined as a finally divided siliceous or aluminous material which, in the presence of water and calcium hydroxide will form a cemented product. The cemented products are calcium-silicate-hydrates and calcium-aluminate-hydrates. These are essentially the same hydrates that form during the hydration of Portland Cement. Clay is a pozzolan as it is a source of silica and alumina for the pozzolanic reaction. The aggregate including natural stone aggregate or non-hazardous industrial waste adds structure strength and bulk to the final mix.
The process of creating a stabilized road base using an aggregate including non-hazardous industrial waste and oil and gas waste material may incorporate a water based chemical agent such as waste cement, varying amounts of aggregate and waste to produce a cold mix, stabilized road base product. An aggregate crusher may process the inert material (typically aggregate including the non-hazardous industrial waste or natural stone aggregate), into the size and texture required (from, for example xc2xdxe2x80x3 to 4xe2x80x3). The aggregate is added to the treated oil and gas waste material at a desired ratio. It has been found that an approximate ratio of one-to-one treated oil and gas waste material to aggregate provides a good mix. This could vary depending upon the degree of contamination or the quality of the oil and gas waste. A chemical reagent is added to congeal the mixture. An asphalt emulsifier is added to create an asphalt stabilized road base. The resulting product is a stabilized road base that not only is of a superior grade, but will not leach hydrocarbons, chlorides or RCRA metals in excess of constituent standards set forth in the Clean Water Act.
In order to further the environmental objectives of the present invention, it is desirable to isolate the oil and gas waste material from the environment prior to mixing. Thus, while the aggregate may be stored on the ground, oil and gas waste material should be stored surrounded by a berm and/or placed on a cement pad, or otherwise isolated by a physical barrier that will prevent leaching of liquid contaminates into the soil. This also prevents storm water runoff. The manufactured road base typically is mixed, processed, and likewise stored surrounded by an earthen berm and on a cement pad and/or other physical barrier that will prevent leaching of liquid contaminates into the soil. Thus, the present invention provides a novel method that will produce grade road base material.
Among the objectives of the present invention are to:
a. combine treated oil and gas waste material with aggregate to produce a stabilized road bed composition.
b. reduce waste from oil drilling, and construction/demolition and manufacturing;
c. reduce the use of new materials for roadbeds;
d. provide a method for producing roadbed material at a lower cost than conventional methods;
e. provide methods of treating oil and gas waste material to yield a material that can be used for preparing a stabilized roadbed and also yield clean mud and water;
f. combine treated oil and gas waste material with non-hazardous industrial waste or naturally occurring material to yield an environmentally safe, usable, stabilized road bed composition;
g. provide simple methods of removing a liquid component from oil and gas waste material;
h. recycle aggregate waste from construction, demolition and manufacturing sites; and
i. provide for a single site or location to which oil and gas waste is transported and at which it is treated and mixed to a road base composition.